Recently, as technology related to a smart vehicle has increased, attempts to add various functions to a vehicle have been developed to first achieve self-driving. Accordingly, a lane maintaining assist system (e.g., a system of maintaining a specific lane) shows sufficient performance within a range in which a lane is clear and various types of road conditions do not frequently occur, as in an express highway and therefore has widely used in vehicles. Further, an electronic stability control (ESC) maintains stability of a vehicle using a difference between an Ackermann yaw rate based on a steering angle and a current yaw rate to prevent instability of vehicle behaviors (e.g., under steer and over steer) within a critical situation.
The lane maintaining assist system according to the related art secures a stable section in which it may be operated only before the vehicle reaches the critical situation, and therefore may not lead to the maximum performance of the vehicle and may cause an oversteering situation. Further, the electronic stability control according to the related art determines a bank (e.g., an incline) angle using only a sensor of the vehicle and thus may have reduced determination reliability regarding whether the vehicle is driving on a bank road and has a limitation at a portion at which the critical situation at the bank road (e.g., an inclined or banked road) is sensed. Further, when a steering control system fails while the lane maintaining assist system and a smart cruise control are operated together, the related art outputs only a warning alarm for a driver to sense the situation but does not yet provide a method which may cope with the situation.